For example, a pressurized water reactor (PWR) in a nuclear power plant uses light water as a nuclear reactor coolant and a neutron moderator, fills an entire reactor core with not-boiled, high-temperature and high-pressure water, transfers the high-temperature and high-pressure water to a steam generator to generate steam by heat exchange, and transfers the steam to a turbine generator to generate power.
Such a nuclear power plant needs a periodical inspection of a structure and the like in order to secure sufficient safety and reliability. If any failure is found out as a result of inspections, a necessary part related to the failure is repaired. When such various works are performed in the nuclear power plant, it is necessary to reduce an amount of radiation acting on a worker.
Examples of such an existing radiation shielding method and a radiation-shielding device are disclosed in Patent Literature 1 described below. In the radiation shielding method and the radiation-shielding device disclosed in Patent Literature 1, shielding is performed such that a hollow vessel is disposed at a predetermined portion of a body to be shielded, a fluid is sent out to the vessel by a fluid sending-out means through a hose while a granular shielding material is supplied to the fluid by a shielding material supply means, so that the shielding material is transferred into the vessel through the hose and the vessel is filled with the shielding material, and the body to be shielded is provided with the vessel filled with the shielding material.